1. Technical Field
The present invention relates to a method for producing an L-amino acid utilizing a bacterium and, in particular, a method for producing an L-amino acid utilizing a fatty acid or an alcohol such as glycerol as a raw material. The present invention also related to a bacterium which can be used in the method, and a gene which can be used for construction of the bacterium. L-Amino acids are industrially useful as additives for animal feeds, components of health foods, amino acid infusions, and so forth.
2. Background Art
In the industrial production of L-amino acids by fermentation, saccharides, i.e., glucose, fructose, sucrose, blackstrap molasses, starch hydrolysate, and so forth, are used as a carbon source. Moreover, methods for producing an L-amino acid using a fatty acid (International Patent Publication WO2009/142286) and glycerol (U.S. Patent Published Application No. 2009/093029) as a carbon source have been disclosed.
For Escherichia bacteria belonging to the family Enterobacteriaceae, a method has been reported for inducing adaptive evolution by performing subcultures under a specific condition (Fong, S. S. et al., 2005, Genome Res., 15:1365-1372, etc.). Moreover, in the chromosome of an adaptive evolution-induced bacterium, the mutation corresponding to the evolution can be searched for and identified by such a method as the CGS method described in Herring, C. D. et al., 2006, Nat. Genet., 38:1406-1412.
The RpsA protein is also called ribosomal protein S1, and it is indispensable for the growth of Escherichia coli (Sorensen, M. A. et al., 1998, J. Mol. Biol., 280(4):561-569). The RpsA protein is known as the largest protein among proteins which constitute the 30S subunit of the ribosome, and it is known to control binding of the 16S rRNA in the 30S subunit and the SD sequence in mRNA (Komarova, A. V. et al., 2002, RNA, 8(9):1137-1147).
However, the ability to utilize fatty acids and alcohols such as glycerol, and abilities to produce L-amino acids from these carbon sources via adaptive evolution has not been analyzed, and the relation between mutation of the bacterial RpsA protein and L-amino acid productivity has not previously been reported.